Searching for the Missing Searching for the Missing Link: Discovering Implicit Link: Discovering Implicit

Structure in Spatial Structure in Spatial HypertextHypertext

Searching for the Missing Searching for the Missing Link: Discovering Implicit Link: Discovering Implicit

Structure in Spatial Structure in Spatial HypertextHypertext

By: Catherine Marshall & Frank ShipmanBy: Catherine Marshall & Frank Shipman

Presented by: Travis GadberryPresented by: Travis Gadberry

Introduction• Role of links in hypertext• Links reconsidered• Linkless Structure in 3 Hypertexts• Perceiving Hypertext• Implementation

Role of Links in Hypertext • Serve two functions

– Vehicle for traveling from one segment of text to another– Articulate specific semantics for interconnection

• Structure as semantic basis– Where does structure lie?– How is structure constrained?– How is structure conveyed?

Links Reconsidered• How does hypertext become implicitly structured?

– If viewed as textual objects arranged in space,– Hypertext can have structure without conventional links– Reader/Author can perceive intended structures in space– If structure is perceived by heuristic algorithm, it can be

simulated and replace explicitly defined structure

• Why does hypertext become implicitly structured?– People have difficulty articulating why they link objects– Accustomed to arranging objects in space– Some current software allows for spatial arrangement

already

Linkless Structure in 3 Hypertexts• Samples collected

– 3 systems used – 8 samples collected– Each was result of long-term info. management /

analysis– Encoded in generic representation for processing– Objects were assigned basic types based on

appearance

• Systems Used:– NoteCards– Virtual Notebook System– Aquanet (no relation to Aqua-man)

NoteCards

Virtual Notebook System

Aquanet

Perceiving Hypertext• Layout-based structures

– Lists & aggregates– All objects treated equally

Perceiving Hypertext• Layout & Type based structures

– Taxonomic set detection– Composites are identifiable

The Implementation• Why to identify implicit structures

– Represent simple but repetitive info.– Allows structures to emerge gradually– Can improve communication about how

a space is used– Helps users notice, express, and

maintain the regular structure of their domain

The Implementation• How structure is analyzed

– Iterative, bottom-up parse– Structure precedence

• Aggregates• Lists• Composites

The Implementation

Testing• Number of objects detected in

– Human generated hypertext– Computer generated (random)

hypertext

• Results– Disorganized structures (not easily

perceived by humans) are not perceived by the algorithm

Conclusions• Spacialized text allows authors to create very

volatile hypertexts• Can easily convey perceptual relationships to

reader• Not navigable – node/link system constrains

links to assist navigation• Idiosyncratic and ambiguous• Future work includes more graphical

recognition and scaling/real world testing

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